Liquid laundry starch



United States Patent O fiice 2,994,615 Patented Aug. 1, 1961 2,994,615LIQUID LAUNDRY STARCH John W. McDonald, Decatur, 111., assignor to A. E.

Staley Manufacturing Company, Decatur, 111., a corporation of DelawareNo Drawing. Filed Oct. 9, 1957, Ser. No. 689,028 7 Claims. (Cl. 106-213)This invention relates, generally, to improvements and innovations inliquid laundry starch compositions which are stabilized and haveprolonged shelf life, and which are characterized by their freedom fromcorrosive action on garments and fabrics in the presence of metalattachments such as metal zippers, buttons, hooks, and ornaments.

Liquid laundry starches have become increasingly popular, particularlyfor home laundry use, since starch in this form obviates the need forpreparing a starch dispersion each time starch is needed. It is, ofcourse, well known that the ordinary starch dispersions prepared at homedo not keep well and therefore itis the practice to prepare only enoughfor immediate needs and any extra amount is usually discarded. Not onlyis this practice wasteful of the starch, but in addition there is littleuniformity in the Starch dispersions prepared under home conditions.

By the designation liquid laundry starch as used herein and in theappended claims, it is intended to designate a commercial product ofhigh uniformity which is stable under ordinary conditions encountered inmerchandising, storage and transit so as to have a prolonged and goodshelf life whereby it will be and remain in excellent condition when itreaches the housewife for use by her over a substantial period of time.An ordinary solution or dispersion of starch consisting only of starchand water will not meet these rigid conditions so as to constitute aliquid laundry starch within the above designation.

Numerous addition agents have from time to time been incorporated inliquid laundry starches with a view of making suitable products. Ingeneral, the prior art has suggested addition of various salts,particularly common salt or sodium chloride, to impart many of thedesired properties. Major functions of these salts are to stabilize thepaste or impart resistance to cold, so that the product will resistfreezing or other undesired change during shipment and during storage inunheated warehouses or storage rooms, and to prolong shelf life undernormal store conditions.

The stabilizing of the liquid laundry starch products is desirable, notonly from a standpoint of providing resistance to freezing and cold, butalso in inhibiting and preventing separation of the ingredients in theproduct if it is exposed to low temperatures. The liquid laundry starchproducts of this type tend, under low temperature conditions, to losetheir original homogeneous character with the result that some of theingredients may settle out or form layers. Once this occurs, it may notbe possible to re-constitute the product to its original condition, evenupon vigorous mixing or shaking.

While the electrolyte salts previously used may impart adequateresistance to these undesirable changes or developments in a liquidlaundry starch product, a trouble some defect has been traced to theincorporation or presence of these strong electrolyte salts in liquidlaundry starch compositions. Thus, it was discovered in connection withthe making of the present invention that when clothes or garments havingmetallic zippers, ornaments, fasteners, etc., are'starched with a liquidlaundry starch containing a strong electrolyte salt such as ordinarysalt, as a Winterizing or stabilizing agent, the fabrics often weakened,and were even completely eaten through. Originally, the cause of thedamage was obscure, but it Was established that it was due to anelectro-chemical corrosive action which occurred, particularly duringthe conditioning, when the damp clothes were rolled up and metallicfasteners or ornaments were in intimate contact with the dampsalt-containing starch compositions. The action of the strong acidsgenerated was accentuated when brought into contact with a hot iron,resulting in the formation of many holes and scorching in the fabrics.

According to United States Patent 2,796,354, the foregoing objectionablebehavior is prevented by replacing the strong electrolyte stabilizingsalts with a mixture of borax and sodium bicarbonate. These two salts,being salts of Weak acids, cannot yield corrosive acids by electrolysis.

According to the present invention, it was discovered that a furthersubstantial improvement in the stabilization and ironing properties ofliquid laundry starches was obtained by eliminating the sodiumbicarbonate. Sodium bicarbonate catalyzes or enhances the browning orscorching of starch when heated to pyrolyzing temperature. Thus, sodiumbicarbonate in a liquid laundry starch contributes to the undesirableyellowing of a starched fabric when ironed at an excessively hightemperature. In other words, elimination of bicarbonate makes the liquidlaundry starch more fool-proof with respect to the scorching problem.

It was also discovered that any of the soluble borates, including thefree boric acids, are satisfactory stabilizing agents and incapable ofproducing the objectionable behavior traced to strong electrolytes, asmentioned above. Satisfactory protection against damage by lowtemperature storage is obtained by the use of 1 to 4 parts by weight ofthe borates and boric acid, or mixtures thereof (calculated as anhydrousmaterial) per parts by weight of a liquid laundry starch. It is to beunderstood that the product may also contain relatively minorproportions of additives such as water softeners, soaps, dyes, perfumes,and optical whitening and brightening agents.

The preferred stabilizing agent is a mixture of two parts by weight ofborax (Na B O .10I-I O) to one part by weight of ortho-boric acid (H BOadded in the proportion of 3% of the weight of the finished liquidlaundry starch product. Use of the preferred kind and proportion sodiumtetraborate (Na- 3 0 1011 0) sodium metaborate (NaBO .2H O), lithiummetaborate (Li B O .8l-I O), potassium pentaborate (KB O .4H O),potassium metaborate (K B O 3H O), potassium tetraborate and sodiumorthoborate (N33BO3). In general, any boric acid and water solubleborate, or mixture thereof, is a suitable stabilizing agent for liquidlaundry starches according to my invention.

The pH of the finished product will depend largely upon the amount andkind of stabilizer used. If alkali metal borates predominate, the pHwill be higher than if the stabilizing agent consists mostly of boricacids. An acceptable range of pH is about 7 to about 10. Above 10 pH,there is increased tendency of the hot iron to yellow the starchedfabric, and below 7 pH, the product may thicken too much.

Accordingly, the principal object of the invention is the provision ofan improved liquid laundry starch sta- 9 a.) bilized with suitableproportions of borates and/or boric acids, which stabilizing ingredientsdo not lead to the production of corrosive acids during use of thestarch, and which liquid laundry starch may also contain relativelyminor amounts of additives such as Water softeners, soaps, ironing aids,preservatives, dyes, fluorescent whitening agents, and perfumes.

Certain other objects of the invention will, in part, be obvious andwill, in part, appear hereinafter.

For a more complete understanding of the nature and scope of theinvention, reference may now be had to the following detaileddescription thereof wherein certain presently preferred formulations areset forth in the examples not only for the purpose of instructing thoseskilled in the art as to the manner in which the invention may bepracticed but also to suggest to them other embodiments of a similarnature coming within the scope of the claims.

Various types of starch may be used in accordance with the presentinvention to prepare liquid laundry starch compositions. The starch maybe obtained from corn, potates, rice, waxy maize, sorghum, and othersources. In general, corn starch is preferable. While raw starch may beused satisfactorily, improved results are obtained by using starch whichhas been suitably modified or converted by chemical or enzymatic actionas is well known in the art. For example, hypochlorite oxidized starchesand acid treated starches may be used to advantage. It has been foundthat a satisfactory range for a starch concentration is from about to15% by weight.

In preparing the liquid laundry starch product, the following procedureis preferred: Mix the starch with water until the desired starchconcentration is obtained. Then stir in the water softener, soap andironing aid (such as sulfonated castor oil) if any of these ingredientsare used. Thoroughly paste the starch by heating the mixture to itsboiling point at atmospheric pressure (200 215 F.) and hold it at theboiling point for thirty minutes. Then cool the cooked mixture to about140 F., stir in the boratesand/or boric acid, also the preservative andperfume if they are used.

Reference may now be had to the following examples for more detailedinformation as to preferred and illustrative embodiments of theinvention.

Example 1 Grams Water 1000 Starch (e.g., cornstarch) 101 Borax (Na B O.10H O) 20 Ortho-boric acid (H BO Sodium hexametaphosphate 2 Neutralsoap 0.3 Sulfonated castor oil 0.2 Perfume 0.125 Phenyl mercuric acetate0.02 Monastral Blue BWD dye 0.005

In general, in Example 1, the mixture of borax and ortho-boric acid maybe replaced by one or more of the following:

The starch is added to the water at sub-pasting tem- 1 perature withstirring to form a thin slurry. The Water softener (sodiumhexametaphosphate), sulfonated castor oil, soap, and dye are stirred inand the mixture is heated to boiling and maintained at that temperaturewith gentle agitation for thirty minutes. The cooked mixture is thencooled to 140 F. and the remaining 7 ingredients are stirred in. Theresulting homogeneous product is then ready to be packaged in containersof desired construction and size.

The purpose of the thirty minute boiling period is to paste the starchthoroughly and thus yield a stable paste or dispersion, one that willnot deposit an observable layer of swollen starch granule fragments atthe bottom of the container on standing. Less vigorous pastingprocedures will yield products With satisfactory starching and ironingqualities, particularly if the product is stirred or shaken in thecontainer before it is applied to the fabric.

The foregoing ingredients may be mixed and processed as described inExample 1.

Example 3 Grams Water 1000 Starch -(e.g., cornstarch) 150 Borax 40Ortho-boric acid 20 Sodium hexametaphosphate 2 Neutral soap 0.3Sulfonated castor oil 0.2 Perfume 0.125 Phenyl mercuric acetate 0.02 Dye(Monastral Blue BWD) 0.005

The foregoing ingredients may be mixed and processed as described inExample 1.

Example 4 Grams Water 1000 Starch (e.g., cornstarch) Borax l0Ortho-boric acid 15 Sodium hexametaphosphate 2 Neutral soap 0.3Sulfonated castor oil 0.2 Perfume 0.125 Phenyl mercuric acetate 0.02 Dye(Monastral Blue BWD) 0.005

The foregoing ingredients may be mixed and processed as described inExample 1.

Example 5 Grams Water 1000 Starch (e.g., cornstarch) 100 Borax 40=Ortho-boric acid 20 The starch is cooked with the water as described inExample 1. The borax and boric acid are added to the starch paste afterit has been cooled to about F.

Although the liquid laundry starch of Example 5 is inferior to those ofExamples 1-4 with respect to apearance, shelf life (i-.e., resistance toseparation into visible layers and to spoilage with yeasts and molds),and ironing qualities, it is an example of a useful liquid laundrystarch stabilized against deterioration during cold weather storage withingredients which do not produce corrosive acids during use of theproduct.

Example 6 Grams Water 1000 Starch (e.g., cornstarch) 100 Borax 20Orthoboric acid 10 Sodium hexametaphosphate 10 Neutral soap 0.3Sulfonated castor oil 0.2 Perfume 0.125 Phenyl mercuri acetate 0.02 Dye(Monastral Blue BWD) 0.005

The foregoing ingredients are mixed and processed as described inExample 1.

Example 7 Grams Water 1000 Starch (e.g., cornstarch) 100 Sodiummetaborate (NaBO .2H O) 10 Ortho-boric acid 10 Sodium hexametaphosphate2 Neutral soap 0.3 Sulfonated castor oil 0.2 Perfume 0.125 Phenylmercuri acetate 0.02 Dye ('Monastral Blue BWD) 0.005

The above ingredients are mixed and processed as de- The foregoingingredients are mixed and processed as described in Example 1.

Example 9 Grams Water 1000 Starch (e.g., cornstarch) 100 Borax 25 Sodiumhexametaphosphate Sulfonated castor oil 0.2 Neutral soap 0.3 Perfume0.125 Phenyl mercuric acetate 0.02 Dye (Monastral -Blue BWD) 0.005

The foregoing ingredients are mixed and processed as described inExample 1.

Example 10 Grams Water 1000 Starch (e.g., cornstarch) 100 Ortho-boric d12 Sodium hexametaphosphate 2 Neutral soap 0.3 Sulfonated castor oil 0.2Perfume 0.125 Phenyl mercuric acetate 0.02

Dye (Monastral Blue BWD)--..... 0.005

The foregoing ingredients are mixed and processed as? described inExample 1.

It will be noted that in the foregoing examples the starch concentrationvaries from 5.1% to 12.4% of the total composition, and that theconcentration of combined borates and boric acid, calculated asanhydrous materials, varies from 1.1% to 3.5%.

The use of sodium hexametaphosphate, or equivalent sequestering agent,is desirable where there is need to inhibit the formation ofobjectionable precipitates, particularly when the product is made withhard water. Thus the sequestering agent in such instance will prolongthe shelf life of the product.

The use of minor quantities of sulfonated castor oil, or equivalentmaterial, is desirable because the oil functions as an ironing aid orlubricant, and because it fre, quently contributes to shelf life of theproduct.

A preservative such as phenyl mercuric acetate is useful becauseotherwise the product is subject to erratic spoilage by microorganisms,yeasts and molds in particular.

Suitable dyes and perfumes are added as desired.

In the appended claims, the concentration of stabilizing agent in thefinished product refers to parts by weight of anhydrous agent per partsby weight of finished liquid product.

Having fully described my invention, what I claim as new is:

1. A scorch-resistant freeze-thaw stable liquid laundry starchcomposition that consists essentially of an aqueous starch paste ofabout 5% to about 15% of starch by weight and dissolved therein asstabilizing ingredient about 1% to about 4% (by weight of the paste) ofa material selected from the group consisting of boric acids,watersoluble salts of boric acids and mixtures thereof, said compositionhaving a pH within the range of about 7 to 10.

2. A scorch-resistant freeze-thaw stable liquid laundry starchcomposition that consists essentially of an aqueous starch paste ofabout 5% to about 15% starch by weight and dissolved therein (1) up toabout 1% by weight of sodium hexametaphosphate and (2) as stabilizingingredient about 1% to about 4% (by weight of the paste) of a materialselected from the group consisting of boric acids, water-soluble saltsof boric acids and mixtures thereof, said composition having a pH withinthe range of about 7 to 10.

3. The laundry starch composition of claim 1 in which the material is amixture of a boric acid and a watersoluble salt of a boric acid.

4. A scorch-resistant freeze-thaw stable liquid laundry starchcomposition that consists essentially of an aqueous starch paste ofabout 5% to about 15% starch by weight and dissolved therein about 1% toabout 4% by weight of a mixture of about two parts borax to about onepart orthoboric acid, said composition having a pH within the range ofabout 7 to 10.

5. The method of preparing a liquid-laundry-starch,freeze-thaw-stabilized composition comprising heating starch with waterto form a starch paste and dissolving in the paste thus formed as thestabilizing ingredient a material selected from the group consisting ofthe boric acids, their water-soluble salts, and mixtures thereof, theweight concentration of starch being from about 5% to about 15% of saidcomposition and the weight concentration of said material being fromabout 1% to about 4% of said composition, and adjusting the pH of saidcomposition, as necessary, to a value in the range of 7 to 10.

6. The method of preparing a freeze-thaw-stabilized,liquid-laundry-starch composition comprising heating starch with waterto form a starch paste and dissolving in the paste (1) sodiumhexametaphosphate and (2) as the stabilizing ingredient a materialselected from the group consisting of the boric acids, water-solublesalts of the boric acids and mixtures thereof, the Weight concentrationof starch ranging from about 5% to about 15% of said composition, theWeight concentration of sodium hexametaphosphateranging from about 0.01%to about 1% of said composition and the weight concentration of saidmaterial ranging from about 1% to about 4% of said composition, andadjusting the pH of said composition, as necessary, to a value in therange of 7 to 10.

7. The method of claim 6 in which the material is a mixture of borax andorthoboric acid in a weight ratio of about 2: 1.

References Cited in the file of this patent UNITED STATES PATENTS Peckeret al. July 15, 1947 Renold Feb. 1, 1955 Fuller June 18, 1957 McCombs eta1 Jan. 14, 1958 Todd Dec. 23, 1958 OTHER REFERENCES Ralph W. Kerr:Chemistry and Industry of Starch, Academic, 1950, page 82.

1. A SCORCH-RESISTANT FREEZE-THAW STABLE LIQUID LAUNDRY STARCHCOMPOSITION THAT CONSISTS ESSENTIALLY OF AN AQUEOUS STARCH PASTE OFABOUT 5% TO ABOUT 15% OF STARCH BY WEIGHT AND DISSOLVED THEREIN ASSTABILIZING INGREDIENT ABOUT 1% TO ABOUT 4% (BY WEIGHT OF THE PASTE) OFA MATERIAL SELECTED FROM THE GROUP CONSISTING OF BORIC ACIDS,WATERSOLUBLE SALTS OF BORIC ACIDS AND MIXTURES THEREOF, SAID COMPOSITIONHAVING A PH WITHIN THE RANGE OF ABOUT 7 TO 10.